Most fungal viruses have been identified in plant pathogens, whereas the presence of viral particles in human-pathogenic fungi is less well studied. In the present study, we observed extrachromosomal double-stranded RNA (dsRNA) segments in various clinical isolates of Malassezia species. Malassezia is the most dominant fungal genus on the human skin surface, and species in this group are considered etiological factors of various skin diseases including dandruff, seborrheic dermatitis, and atopic dermatitis. We identified novel dsRNA segments, and our sequencing results revealed that the virus, named MrV40, belongs to the Totiviridae family and contains an additional satellite dsRNA segment encoding a novel protein. The transcriptome of virus-infected Malassezia restricta cells was compared to that of virus-cured cells, and the results showed that transcripts involved in ribosomal biosynthesis were downregulated and those involved in energy production and programmed cell death were upregulated. Moreover, transmission electron microscopy revealed significantly larger vacuoles in virus-infected M. restricta cells, indicating that MrV40 infection dramatically altered M. restricta physiology. Our analysis also revealed that viral nucleic acid from MrV40 induced a TLR3 (Toll-like receptor 3)-mediated inflammatory immune response in bone marrow-derived dendritic cells, suggesting that a viral element contributes to the pathogenicity of Malassezia.

中文翻译：

---

一种新型病毒改变了马拉色菌细胞中的基因表达和液泡形态，并诱导了TLR3介导的炎性免疫反应。

在植物病原体中已鉴定出大多数真菌病毒，而对人致病性真菌中病毒颗粒的存在的研究较少。在本研究中，我们在马拉色菌属的各种临床分离株中观察到了染色体外双链RNA（dsRNA）片段。马拉色霉菌是人类皮肤表面上最主要的真菌类，并且该组中的物种被认为是各种皮肤病的病因，包括头皮屑，脂溢性皮炎和特应性皮炎。我们鉴定了新的dsRNA片段，我们的测序结果表明，该病毒名为MrV40，属于Totiviridae家族，并含有一个编码新蛋白质的卫星dsRNA片段。病毒感染的转录组将马拉色菌限制性内质网细胞与病毒固化的细胞进行了比较，结果表明，参与核糖体生物合成的转录本被下调，而涉及能量产生和程序性细胞死亡的转录本被上调。此外，透射电镜显示在病毒感染的限制支原体细胞中明显更大的液泡，表明MrV40感染显着改变了限制性支原体生理。我们的分析还显示，来自MrV40的病毒核酸在骨髓来源的树突状细胞中诱导了TLR3（Toll样受体3）介导的炎症免疫反应，表明病毒元素有助于马拉色菌的致病性。